gunk in tube: what to do?

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Mike Teachman
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gunk in tube: what to do?

Post by Mike Teachman »

I'm looking for ideas on cleaning out gunk that is collecting at the two pinch points in our 45W LO tube. I think the gunk originates from water tub algae that gets pumped thru the tube and then collects at the two narrow points in the glass tube. Water flow seems OK right now, but I am concerned that further buildup will put tube cooling at risk.

I'm considering trying to reverse flush the tube with water and some cleaning additive. Vinegar seems like a viable additive that should not degrade the pump or silicone tubing.

Can anyone in the laser community offer advice?

thanks!
Axeman
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Re: gunk in tube: what to do?

Post by Axeman »

I just recently did this as well, had some gunk built up in my tubes.

I did a mixture of warm water, bit of vinegar and a bit of bleach to give my whole system a good cleaning. I reversed flow and forward flow over and over until the gunk was dislodged and cleaned out. After about an hour of letting it flow on it's own, it cleared up. I quickly switched back to the standard distilled afterwards and it runs like a champ!

Been doing the laser thing for 4+ years and haven't had issues yet doing this.
SWMS
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Re: gunk in tube: what to do?

Post by SWMS »

I’ve had problems with mould /gunk too.

The best thing to do is clean your buckets and lines with a sterilising solution. That could be a weak bleach water mix or the stuff they use for cleaning lines in a pub. Then add something like Milton sterilising fluid or iodine every few weeks. It doesn’t matter if it’s distilled or not you will get mould growth.
Mike Teachman
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Re: gunk in tube: what to do?

Post by Mike Teachman »

We discovered a good way to clean out our tube using Oxiclean powder. Here is the procedure:
  1. Reverse water pump connections so the water will flow from the laser emitting end to the high voltage end (we're "backflushing" the tube)
  2. 3/4 fill a gallon bucket with warm water
  3. add 4 scoops of Oxiclean. The scoop was provided with the product. Mix to dissolve.
  4. add pump to bucket. Return tubing goes into bucket
  5. start pump
  6. run pump for about 1/2 hr
  7. flush out tube with clean water to remove any Oxiclean
  8. re-connect water pump so water flows from HV end to emitting end
Why it works: The Oxiclean produces a mixture of bubbles and water. The bubbles pummel the gunk attached to the tube walls causing it to detach from the tube.

This procedure was very effective for us as shown in the before/after photos.
feb2018-2-b4Clean (Medium).JPG
feb2018-2-afterOxiclean (Medium).JPG
feb201-1-b4Clean (Medium).JPG
feb2018-1-afterOxiclean (Medium).JPG
SWMS
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Re: gunk in tube: what to do?

Post by SWMS »

So whilst I know it’s not that helpful now you have it.

Here’s my so far tried and tested method for never getting gunk In the tube.

Wash all lines and tubs with a bleach and water solution.
Do it again.
Do it again. :D

Use de ionised water - less minerals in it and less oxygen.

Now your experience may be different but I thought I had algae. It might well be a bit of algae. However. I was putting in anti algae solution and it was still growing. Also Algae likes sunlight and it’s not like the coolant was getting lots of that.

I tried a mild solution of Milton. I was still getting ghostly apparitions in the water

Then I discovered mould can grow in water. It also LOVES any temperatures over 10.5 degrees centigrade. Rather than be putting bleach in my system which didn’t seem to work very well I opted for iodine! It kills anything in water and makes it drinkable so it’s good enough for the laser.

When the laser isn’t in use I run my chiller at 10.5 degrees c. It’s a pond chiller so it’s used to running all the time. Every two weeks I pop some iodine in.

I’d also recommend you get some fine pond pump filter. The ones they come with are like mesh.

Finally i’d Recommend you look up enheim double stop taps. This enables you to disconnect your coolant supply from the laser and change it without getting water everywhere.

It took me ages to get to this stage and there is no good documentation on it.
Mike Teachman
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Re: gunk in tube: what to do?

Post by Mike Teachman »

SWMS,

Thanks a TON for taking the time to share all of your experience on remedies to prevent growth in the tubes. This information is going to save our makerspace a lot of trial and error. I'm going to try iodine in the next water change out. Your mould theory is interesting - I see the same as you - anti algae does nothing to prevent the tube and tub gunk. A small dose of Clorox is our current attempt to minimize growth. Early days to see if this is working, or not.

I'm going to look into the double stop taps. Presently I have to wiggle the tubing off a barbed connector when I change out the water - rather tedious.
SWMS
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Re: gunk in tube: what to do?

Post by SWMS »

No probs.

By the way. Leave your pump on. It’ll keep the nasties from setting up home in one place and keep them filtering through the pump.
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